a. Field of the Invention
The invention relates to an elevating mechanism for a projection apparatus.
b. Description of the Related Art
Referring to FIG. 1, typically, in order to adjust the position of an image projected from a projection apparatus 100, designers commonly equip the projection apparatus 100 with an elevating mechanism 102. The image is projected onto a screen 104 at a proper position by adjusting an angle of elevation θ of the projection apparatus 100 (or the height of a front end of the projection apparatus 100) through the elevating mechanism 102. More specifically, the elevating mechanism 102 is capable of lifting the front end of the projection apparatus 100 to change the height of the image projected from the projection apparatus 100.
FIG. 2A and FIG. 2B show schematic diagrams of an elevating mechanism 200 disclosed in Taiwan patent no. I286261. Referring to FIG. 2A, a moveable leg 220 is retracted in a base 210 before the height adjustment is performed. Further, a positioning part (not shown) of a frame 252 is inserted into a positioning slot 222 of the moveable leg 220 to fix the moveable leg 220 on the base 210. Referring to FIG. 2B, when a user pushes the button 254, the positioning part of the frame 252 leaves the positioning slot 222, and hence the movable leg 220 moves downwardly and sticks out from the opening 216 of the base 210 by the elastic force of a spring 234. When the movable leg 220 stretches to a proper position, the user may release the button 254 to enable an elastic body (not shown) to push the frame 252, so that the positioning part of the frame 252 may insert the slot 222 of the movable leg 220 to fix the movable leg 220 on the base 210 again.
However, according to the above design, though the movable leg 220 may rise and fall rapidly, the height of the movable leg 220 fails to be finely tuned. Therefore, the accuracy of the height adjustment for the projection apparatus cannot be further improved. Further, Taiwan patent no. M281198 discloses a position adjustment device of a projector having a main body, a stop pin, at least one elastic member and a support screw. When the stop pin is pushed inwardly, a part of the stop pin comes off threads of the support screw to enable the main body to move upwardly and downwardly. Besides, Taiwan patent no. I312439 discloses a projection apparatus having a projection body, a support and a pivoting element. The pivoting element is pivoted on the projection body, and thus the projection body is suitable for swinging over the pivoting element. Therefore, a user is able to rapidly adjust an elevating angle or an inclination of the projection body. In addition, Taiwan design patent no. D100458 discloses a profile of a foot pad for a projection apparatus.